Addressing waste problems in rural communities: The Kigalamizi Village Case Waste disposal is the process of getting rid of the waste material that people generate. The types of wastes include: gaseous wastes, e.g. carbon monoxide from cars, liquid wastes e.g. sewage, and solid wastes paper, plastic, food scraps refuse or garbage. Wastes can look ugly, smells foul, creates health problems

This refers to open damps and is generally a poor method of disposing refuse and can lead to serious environmental problems. This can actually ruin an area's appearance. They can also provide homes for animals that spread disease. Rainwater can carry harmful substances to to nearby streams and to water used for drinking. Smoke and foul smell e.g. at Kampala city abattoir However, proper land fills can cause little damage to the environment.

Incineration:
This is the process of burning waste products. It can be an alternative to land fills. The process of incineration can lead to serious pollution. This is especially true of incinerators that do not have proper control devices. Incinerators are required to limit the amount of pollution they release because gases, solid particles may be harmful to human health, damage property and kill plants. Ash produced by incineration should be monitored to control pollution to the environment.

Recycling and waste reduction
Recycling is the process of reusing material instead of throwing them away. Recyclables include glass, paper, metals. Waste reduction is the process of producing less waste e.g. using handkerchiefs than using disposable tissues. Indeed few people like to live or work near a garbage disposal site. Recycling and waste reduction are the important methods of waste management. In the late 1980's Americans burried about 73% of the municipal solid waste in land fills, recycled about 13% and burned about 14% in incinerators By Maria R Chertow

Recycling, collection, processing, and reuse of materials that would otherwise be thrown away. Materials ranging from precious metals to broken glass, from old newspapers to plastic spoons, can be recycled. The recycling process reclaims the original material and uses it in new products. In general, using recycled materials to make new products costs less and requires less energy than using new materials. Recycling can also reduce pollution, either by reducing the demand for high-pollution alternatives or by minimizing the amount of pollution produced during the manufacturing process. Recycling decreases the amount of land needed for trash dumps by reducing the volume of discarded waste. Recycling can be done internally (within a company) or externally (after a product is sold and used). In the paper industry, for example, internal recycling occurs when leftover stock and trimmings are salvaged to help make more new product. Since the recovered material never left the manufacturing plant, the final product is said to contain preconsumer waste. External recycling occurs when materials used by the customer are returned for processing into new products. Materials ready to be recycled in this manner, such as empty beverage containers, are called postconsumer waste.

Types of Materials Recycled
Just about any material can be recycled. On an industrial scale, the most commonly recycled materials are those that are used in large quantities—metals such as steel and aluminum, plastics, paper, glass, and certain chemicals.

Steel
There are two methods of making steel using recycled material: the basic oxygen furnace (BOF) method and the electric arc furnace (EAF) method. The BOF method involves mixing molten scrap steel in a furnace with new steel. About 28 percent of the new product is recycled steel. Steel made by the BOF method typically is used to make sheet-steel products like cans, automobiles, and appliances. The EAF method normally uses 100 percent recycled steel. Scrap steel is placed in a furnace and melted by electricity that arcs between two carbon electrodes. Limestone and other materials are added to the molten steel to remove impurities. Steel produced by the EAF method usually is formed into beams, reinforcing bars, and thick plate. Approximately 68 percent of all steel is recycled, making it one of the world's most recycled materials. In 1994 37 billion steel cans, weighing 2,408,478 metric tons (2,654,892 U.S. tons), were used in the United States, of which 53 percent were recycled. In 1995 more than 60 million metric tons (70 million U.S. tons) of scrap steel were recycled in the United States.

Aluminum
Recycling aluminum in the United States provides a stable, domestic aluminum supply amounting to approximately one-third of the industry's requirement. In contrast, most of the ore required to produce new aluminum must be imported from Jamaica, Australia, Surinam, Guyana, and Guinea. About 2 kg (about 4 lb) of ore, a mixture of aluminum oxides called bauxite, are needed to make 0.5 kg (1 lb) of aluminum. The U.S. aluminum industry has recognized the advantage of a domestic aluminum supply and has established systems for collection, transportation, and processing. For this reason, aluminum cans almost always produce a profit in community recycling programs. A number of states require deposits for beverage containers and have established redemption centers at supermarkets. The overall recycling rate of all forms of aluminum is about 35 percent. Cans brought to collection centers are crushed, baled, and shipped to regional mills or reclamation plants. The cans are then shredded to reduce volume and heated to remove coatings and moisture. Next, they are put into a furnace, melted, and formed into ingots, or bars, weighing 10,000 kg (30,000 lb) or more. The ingots go to another mill to be rolled into sheets. The sheets are sent to a container plant and cut into disks from which new cans are formed. The cans are printed with the beverage makers' logos and are shipped (with tops separate) to the filling plant. About 100 billion aluminum beverage cans are used each year in the United States and about 65 percent of these are then recycled. The average aluminum can in the United States contains 40 percent postconsumer recycled aluminum. About 97 percent of all soft drink cans and 99 percent of all beer cans are made of aluminum.

Plastics
Plastics are more difficult to recycle than metal, paper, or glass. One problem is that any of seven categories of plastics can be used for containers alone. For effective recycling, the different types cannot be mixed. Most states require that plastic containers have identification codes so they can be more easily identified and separated. The code assigns a particular number to each of the seven plastics used in packaging. The number 1 refers to polyethylene teraphthalate (PET) and the number 2 refers to high-density polyethylene (HDPE). PET can be made into carpet, or fiberfill for ski jackets and clothing. HDPE can be recycled into construction fencing, landfill liners, and a variety of other products. Plastics coded with the number 6 are polystyrene (PS), which can be recycled into cafeteria trays, combs, and other items. The recycling process for plastic normally involves cleaning it, shredding it into flakes, then melting the flakes into pellets. The pellets are melted into a final product. Some products work best with only a small percentage of recycled content. Other products, such as HDPE plastic milk cases, can be made successfully with 100 percent recycled content. The plastic container industry has concentrated on weight reduction and source reduction. For example, the one-gallon HDPE milk container that weighed about 120 gm (about 4.2 oz) in the 1960s weighed just 65 gm (about 2.3 oz) in 1996. In the United States, the overall recycling of plastic was under 4.7 percent in 1994, with the recycling rate of plastic containers at about 19 percent. Most discarded plastic is in the form of plastic containers. Plastics made up about 11 percent of the waste stream by weight and about 24 percent by volume in 1994. Paper and Paper Products
Paper products that can be recycled include cardboard containers, wrapping paper, and office paper. The most commonly recycled paper product is newsprint. In newspaper recycling, old newspapers are collected and searched for contaminants such as plastic bags and aluminum foil. The paper goes to a processing plant where it is mixed with hot water and turned into pulp in a machine that works much like a big kitchen blender. The pulp is screened and filtered to remove smaller contaminants. The pulp then goes to a large vat where the ink separates from the paper fibers and floats to the surface. The ink is skimmed off, dried and reused as ink or burned as boiler fuel. The cleaned pulp is mixed with new wood fibers to be made into paper again. Paper and paper products such as corrugated board constitute about 40 percent of the discards in the United States, making it the most plentiful single item in landfills. Experts estimate the average office worker generates about 7 kg (about 15 lb) of wastepaper (about 1,500 sheets) per month. Every ton of paper that is recycled saves about 1.4 cu m (about 50 cu ft) of landfill space. One ton of recycled paper saves 17 pulpwood trees (trees used to produce paper). Glass
Scrap glass taken from the glass manufacturing process, called cullet, has been internally recycled for years. The scrap glass is economical to use as a raw material because it melts at lower temperatures than other raw materials, thus saving fuel and operating costs. Glass that is to be recycled must be relatively free from impurities and sorted by color. Glass containers are the most commonly recycled form of glass, and their colors are flint (clear), amber (brown), and green. Other glass, such as window glass, pottery, and cooking utensils, are considered contaminants because they have different compositions than glass used in containers. The recycled glass is melted in a furnace and formed into new products. Glass containers make up 90 percent of the total glass used in the United States. The 1994 recycling rate for glass was about 33 percent. Other uses for recycled glass include glass art and decorative tiles. Cullet mixed with asphalt forms a paving material called glassphalt. Chemicals and Hazardous Waste
Household hazardous wastes include drain cleaners, oven cleaners, window cleaners, disinfectants, motor oil, paints, paint thinners, and pesticides. Most municipalities ban hazardous waste from the regular trash. Periodically, citizens are alerted that they can take their hazardous waste to a collection point where trained workers sort it, recycle what they can, and package the remainder in special leak-proof containers called lab packs, for safe disposal. Typical materials recycled from the collection drives are motor oil, paint, antifreeze, and tires. Business and industry have made much progress in reducing both the hazardous waste they generate and its toxicity. Although large quantities of chemical solvents are used in cleaning processes, technology has been developed to clean and reuse solvents that used to be discarded. Even the vapors evaporated from the process are recovered and put back into the recycled solvent. Some processes that formerly used solvents no longer require them. Nuclear Waste
Certain types of nuclear waste can be recycled, while other types are considered too dangerous to recycle. Low-level wastes include radioactive material from research activities, medical wastes, and contaminated machinery from nuclear reactors. Nickel is the major metal of construction in the nuclear power field and much of it is recycled after surface contamination has been removed. High-level wastes come from the reprocessing of spent fuel (partially depleted reactor fuel) and from the processing of nuclear weapons. These wastes emit gamma radiation, which can cause birth defects, disease, and death. High-level nuclear waste is so toxic it is not normally recycled. Instead, it is fused into inert glass tubes encased in stainless steel cylinders, which are then stored underground. Spent fuel can be reprocessed and recycled into new fuel elements, although fuel reprocessing was banned in the United States in 1977 and has never been resumed for legal, political, and economic reasons. However, spent fuel is being reprocessed in other countries such as Japan, Russia, and France. Spent fuel elements in the United States are kept in storage pools at each reactor site.

Reasons for Recycling
Rare materials, such as gold and silver, are recycled because acquiring new supplies is expensive. Other materials may not be as expensive to replace, but they are recycled to conserve energy, reduce pollution, conserve land, and to save money. Resource Conservation
Recycling conserves natural resources by reducing the need for new material. Some natural resources are renewable, meaning they can be replaced, and some are not. Paper, corrugated board, and other paper products come from renewable timber sources. Trees harvested to make those products can be replaced by growing more trees. Iron and aluminum come from nonrenewable ore deposits. Once a deposit is mined, it cannot be replaced. Energy Conservation
Recycling saves energy by reducing the need to process new material, which usually requires more energy than the recycling process. The amount of energy saved in recycling one aluminum can is equivalent to the energy in the gasoline that would fill half of that same can. To make an aluminum can from recycled metal takes only 5 percent of the total energy needed to produce the same aluminum can from unrecycled materials, a 95 percent energy savings. Recycled paper and paperboard require 75 percent less energy to produce than new products. Significant energy savings result in the recycling of steel and glass, as well. Pollution Reduction
Recycling reduces pollution because recycling a product creates less pollution than producing a new one. For every ton of newspaper recycled, 7 fewer kg (16 lb) of air pollutants are pumped into the atmosphere. Recycling can also reduce pollution by recycling safer products to replace those that pollute. Some countries still use chlorofluorocarbons (CFCs) to manufacture foam products such as cups and plates. Many scientists suspect that CFCs harm the atmosphere's protective layer of ozone. Using recycled plastic instead for those products eliminates the creation of harmful CFCs. Land Conservation
Recycling saves valuable landfill space, land that must be set aside for dumping trash, construction debris, and yard waste. In the United States, each person on average discards almost a ton of municipal solid waste (MSW) per year. MSW is raw, untreated garbage of the kind discarded by homes and small businesses. Waste from industry and agriculture normally is not part of MSW, but construction and demolition wastes are. The United States has the highest MSW discard level of any country in the world. Landfills fill up quickly and acceptable sites for new ones are difficult to find because of objections by neighbors to noise and smells, and the hazard of leaks into underground water supplies. The two major ways to reduce the need for new landfills are to generate less initial waste and to recycle products that would normally be considered waste. In 1994 about 6.8 million metric tons (7.5 million U.S. tons) of food and yard debris were composted in the United States, accounting for about one-sixth of the overall 23.6 percent recycling rate (see Compost). The combined effort of reducing waste and recycling resulted in 41 million fewer metric tons (45 million U.S. tons) of material going to landfills. Solid waste can also be burned instead of buried in the ground. Typically, waste-to-energy (WTE) facilities burn trash to heat water for steam-turbine electrical generators. This WTE recycling keeps another 16 percent of municipal solid waste out of the landfills. Economic Savings
Recycling in the short term is not always economically profitable or a break-even financial operation. Most experts contend, however, that the economic consequences of recycling are positive in the long term. Recycling will save money if potential landfill sites are used for more productive purposes and by reducing the number of pollution-related illnesses. History
People have recycled materials throughout history. Metal tools and weapons have been melted, reformed, and reused since they came in use thousands of years ago. The iron, steel, and paper industries have almost always used recycled materials. Recycling rates were modest in the United States up through the 1960s, although rates increased during World War II (1939-1945). Since the 1960s, recycling has steadily increased. Recycling in the United States between 1960 and 1994 rose from 5.35 million metric tons (5.9 million U.S. tons) per year to 44.7 million metric tons (49.3 million U.S. tons). In 1930 about 7 percent of municipal solid waste was recycled. By 1994 that amount had climbed to 23.6 percent. Experts predict the MSW recycling rate will reach 30 percent by the year 2000. European countries have a long history of recycling and, in some cases, stiff requirements. In 1991 the German parliament approved legislation setting recycling targets of 80 to 90 percent for packaging materials and banned the sale of products from companies that do not cooperate. France has set specific recycling goals. Other countries with significant overall recycling rates include Spain at 29 percent, Switzerland at 28 percent, and Japan at 23 percent.

Contributed By:
Roy A. Hartman
Manufacturing, producing goods that are necessary for modern life from raw materials. The word manufacture comes from the Latin manus (hand) and facere (to make). Originally manufacturing was accomplished by hand, but most of today's modern manufacturing operations are highly mechanized and automated. There are three main processes involved in virtually all manufacturing: assembly, extraction, and alteration. Assembly is the combination of parts to make a product. For example, an airplane is assembled when the manufacturer puts together the engines, wings, and fuselage. Extraction is the process of removing one or more components from raw materials, such as obtaining gasoline from crude oil. Alteration is modifying or molding raw materials into a final product—for example, sawing trees into lumber. Science and engineering are required to develop new products and to create new manufacturing methods, but there are other factors involved in the manufacturing process. Legal matters, such as obtaining operating permits and meeting industrial safety standards, must be adhered to. Economic considerations, such as competition, worldwide markets, and tariffs, control to some degree what prices are set for manufactured goods and what inventories are needed.

History of Manufacturing
Manufacturing has existed as long as civilizations have required goods: bricks to build the Mesopotamian city of Erech (Uruk), clay pots to store grain in ancient Greece, or bronze weapons for the Roman Empire. In the Middle Ages, silk factories operated in Syria, and textile mills were established in Italy, Belgium, France, and England. New routes discovered from Europe to the Far East and to the New World during the Renaissance (14th century to 17th century) stimulated demand for manufactured goods to trade. Factories were built to produce gunpowder, clothing, cast iron, and paper. The manufacturing of these goods was primarily done by hand labor, simple tools, and, rarely, by machines powered by water. Industrial Revolution

The Industrial Revolution began in England in the middle of the 18th century when the first modern factories appeared, primarily for the production of textiles. Machines, to varying degrees, began to replace the workforce in these modern factories. The cotton gin, created by the American inventor Eli Whitney in 1793, mechanically removed cotton fibers from the seed and increased production. In 1801 Joseph Jacquard, a French inventor, created a loom that used cards with punched holes to automate the placement of threads in the weaving process. The development of the steam engine as a reliable power source by Thomas Newcomen, James Watt, and Richard Trevithick in England, and in America by Oliver Evans, enabled factories to be built away from water sources that had previously been needed to power machines. From the 1790s to the 1830s, more than 100,000 power looms and 9 million spindles were put into service in England and Scotland (see Factory System; Industrial Revolution).

Mass Production
In addition to inventing the cotton gin, Eli Whitney made another contribution to the factory system in 1798 by proposing the idea of interchangeable parts. Interchangeable parts make it possible to produce goods quickly because repairs and assembly can be done with previously manufactured, standard parts rather than with costly custom-made ones. This idea led to the development of the assembly line, where a product is manufactured in discrete stages. When one stage is complete, the product is passed to another station where the next stage of production is accomplished. In 1913 the American industrialist Henry Ford and his colleagues first introduced a conveyer belt to an assembly line for flywheel magnetos, a type of simple electric generator, more than tripling production. The assembly line driven by a conveyor belt was then implemented to manufacture the automobile body and motors.

Labor Movement
Labor unions, associations of workers whose goal is to improve their economic conditions, originated in the craft guilds of 16th-century Europe. The modern labor movement, however, did not start until the late 19th-century, when reliable railroad systems were developed. Railroads brought materials from diverse locations for final manufacturing and assembly and created a large demand for industrial labor. Labor unions gained enormous strength after World War II (1939-1945) when the United States had both high inflation and a huge population of factory workers. This combination forced labor unions to negotiate for better contracts and wages, and they achieved significant influence in industry. Today fewer manufacturing jobs and the trend for factories to relocate to foreign countries have combined to diminish the strength of organized labor (see Trade Unions). Military Operations and Manufacturing
When the United States joined the Allies against Hitler in World War II, the country was in its 11th year of economic depression, 17 percent of the workforce was unemployed, and manufacturers were unprepared to mobilize for wartime production. President Franklin Delano Roosevelt succeeded in motivating the industrial complex to invest in new manufacturing facilities through a combination of generous business contracts, tax laws, and patriotism. By 1943 manufacturing capacity had increased dramatically: 10,000 military airplanes were produced a month, and it took only 69 days to build a warship. When World War II ended, the United States was the leading producer of manufactured goods. After the war, part of this vast military manufacturing capacity was converted to create consumer items such as automobiles, furniture, and televisions. The development of the Cold War between Communist and non-Communist powers was accompanied by a buildup of manufactured weapons such as fighter airplanes and bombers, submarines, missiles, and nuclear weapons. The shift to a military manufacturing base accelerated the development of space science and advanced electronics, particularly integrated circuitry, which would eventually become the processing engine for the modern personal computer. Computers, in turn, have helped increase the productivity of modern manufacturing plants because they enable automated design, production, and record keeping (see Computer-Aided Design/Computer-Aided Manufacture). Types of Manufacturing
Manufacturing processes can produce either durable or nondurable goods. Durable goods are products that exist for long periods of time without significant deterioration, such as automobiles, airplanes, and refrigerators. Nondurable goods are items that have a comparatively limited life span, such as clothing, food, and paper.

Iron and Steel Manufacture
Iron manufacturing originated about 3500 years ago when iron ore was accidentally heated in the presence of charcoal. The oxygen-laden ore was reduced to a product similar to modern wrought iron. Today, iron is made from ore in blast furnaces. Oxygen and other elements are removed when the ore is mixed with coke (a material that contains mostly carbon) and limestone and is then blasted by hot air. The gases formed by the burning materials combine with the oxygen in the ore and reduce the ore to iron. This molten iron still contains many impurities, however. Steel is manufactured by first removing these impurities and then adding elements, predominantly carbon, in a controlled manner. Strong steels contain up to 2 percent carbon. The steel is then shaped into bars, plates, sheets, and such structural components as girders (see Iron and Steel Manufacture).

Textile Manufacturing
Raw fibers of cotton, wool, or synthetic materials such as nylon and polyester go through a complex series of processes to form fabrics for apparel, home furnishings, and biomedical, recreation, and aerospace products. In most cases, loose tufts of fiber are straightened, and the thick ropelike slivers are thinned for spinning. In the spinning process, the fibers are twisted to add strength. Synthetic fibers are generally made in a continuous string, but sometimes they go through a texturing process to give them a natural appearance. These twisted fibers, known as yarns, are then woven or knitted into fabrics. Weaving is a process that interlaces two sets of yarns, the warp and filling, in a variety of patterns that impart design and different physical characteristics. Knitting is a technique that loops yarns together to form fabric. The fabrics are then dyed, and finishes applied (see Textiles). Lumber Industry
The lumber industry converts trees into construction materials or the precursor material for pulp and paper. Trees are harvested, debarked, then sawed into usable shapes such as boards and slabs. The lumber is graded for use and quality and then dried in large kilns, or ovens. Lumber is manufactured into boards, plywood, composition board, or paneling. Pulp wood for paper is sent directly to the manufacturer without sawing or drying (see Lumber Industry).

Automobile Manufacturing
The automobile was the first major manufactured item built by a mass production system using cost-effective assembly line techniques. Today, before an automobile reaches its final assembly point, subsystems, such as the engine, transmission, electrical components, and chassis, are fabricated from raw materials in other specialized facilities. The metallic automobile body parts are stamped and welded together by robots into a unibody, or one-piece, construction. This body is then dipped in a succession of chemical baths that rustproof and provide undercoat and paint treatments. During the final assembly, conveyor systems direct all of the components to stations along the production route. The engine, transmission, fuel tank, radiator, electrical systems, body panels and doors, suspension system, tires, and interior accessories are fastened to the chassis. Rigid quality-control standards at every step ensure that the completed vehicle is safe and built to specifications (see Automobile Industry).

Aerospace Industry
The aerospace industry manufactures airplanes, rockets and missiles, among other technologies. The first airplanes were constructed from wood and fabrics; modern airplanes are built from aluminum alloys, titanium, plastics, and advanced textile-reinforced composite materials. As in automobile manufacturing, components such as engines and landing gear are manufactured in separate facilities and then assembled with the wings, rudders, and fuselage to produce the finished airplane. Final assembly is conducted on an assembly line, where the partially manufactured airplane is moved from station to station. Rockets are built on an individual basis. Rocket casings are created by winding high-strength carbon fibers and epoxy resins onto a cylindrical shape. The epoxy hardens and encapsulates the fibers to produce a strong, lightweight material. Solid rocket fuel is put into the body of the rocket. Thrust nozzles and exit cones are then added along with electronic guidance systems and payloads.

Petrochemical Industry
Petrochemicals are manufactured from naturally occurring crude oils and gases. Once removed from the earth, the crude oil is refined into gasoline, heating oil, kerosene, plastics, textile fibers, coatings, adhesives, drugs, pesticides, and fertilizers. Crude oil contains thousands of natural organic chemicals. These are separated by distilling, or boiling off, the compounds at different temperatures. Gases such as methane, ethane, and propane are also released. Methane, when combined with nitrogen and pressurized and heated, yields ammonia, an important ingredient in fertilizers. Simple plastic materials, such as polyethylene and polypropylene, are manufactured by first heating ethane and propane gases and then rapidly cooling them to alter their chemical structure (see Petroleum).

Future Technologies
Manufacturing systems today are designed to recycle many of their components. For example, in the automotive industry, excess steel and aluminum can become scrap stock for new metal, rubber tires can be chopped and mixed with asphalt for new roadways, and engine starters can be remanufactured and sold again. Recycling for newer materials, such as composites (combinations of materials designed with superior physical and mechanical properties), has yet to be developed, however. Emission control will be a critical issue for future manufacturers. Smoke scrubbers must remove dangerous gases and particulates from industrial plant discharges, and manufacturing facilities that dump chemicals into rivers must develop methods of eliminating or reusing these waste products. The economically advantageous automated factory has become the norm. Most automobile engines are manufactured using robotic tools and handling systems that deliver the engine to various machining sites. Computers with sophisticated inventory tracking programs make it possible for items to be assembled and delivered at the manufacturing facility only as they are needed. In demand-activated manufacturing, when an item is sold a computer schedules the manufacture of an item to replace the unit sent to the customer. Engineers use computers to help them design new products efficiently. The Boeing 777 jet, for example, was developed in record time by having its entire design and manufacturing systems created on a computer database rather than using traditional blueprints.

Contributed By:
David Brookstein